This invention relates to exploding wires and more particularly relates to chemical reaction chambers having ultra-high power exploding wire systems for use in enhancing chemical and/or physical reactions.
Investigations have been made into the use of exploding wires or exploding bridge wires, as they are sometimes called, to enhance certain chemical reactions, see "A Thermal Model of Wire Explosions in Methane", B. Siegel and R. L. Johnson, Proceeding of the Fourth Conference on the Exploding Wire Phenomenon, held at Boston, Mass., Oct. 18-20, 1967.
The results of these investigations are encouraging in that exploding wires possess some truly unique features, such as: the capability of (a) injecting energies in the 10 kilocalories and greater per mole range in sub-microsecond time intervals; (b) providing electrical to chemical conversion efficiencies much superior to those provided by other electrical sources, e.g. corona; and (c) producing energy which, in turn, imparts high velocity to the physical mass of those reactants in contact with the exploding wire.
As can be seen from the above, exploding wires (e.g. wires, foils, or layers of metals or semiconductor materials) provide a way of concentrating large amounts of energy into a small space. Reaction times may be as short as a fraction of a microsecond, making the available peak power as well as the average power extremely large. For example, a two farad capacitor charged to 10,000 volts will store 10.sup.8 joules of energy which is approximately the same potential energy in one gallon of gasoline. However, the gallon of gasoline requires 10,000 gallons of air and a relatively long period of time to release its total energy. The same energy stored on the capacitor may be dissipated in a millisecond by dumping the charge into a resistive load. If this resistive load is a metallic or semiconductive material, then it becomes an exploding wire system.
To understand the basic premise involved in an exploding wire system, one only has to consider the common electrical fuse. During normal operations, the current flowing through the fuse is not sufficient to cause a significant voltage drop across the fuse and the fuse therefore has no significant influence upon the overall electrical circuit. However, when the current through the fuse is increased to some value determined by the fuse characteristics, the voltage drop across the fuse becomes sufficient to melt the current conducting element (e.g. wire) in the fuse. This melting process opens up the electrical circuit and current can no longer flow until the fuse is replaced.
The exploding wire concept represents an extreme case of such an electrical fuse. Typically, a bank of electrical capacitors are charged to a high energy and voltage level. The charged bank is discharged, via an appropriate switch, through a series circuit that contains the element, i.e. wire, to be exploded. The current through the exploding wire is many orders of magnitude greater than that necessary to fuse the wire. The extreme resistive heating in the exploding wire causes a near instantaneous vaporization of the wire, itself. An energy balance reveals that the electrical energy stored on the capacitor is converted to useful energy in a variety of ways: (1) the wire is vaporized which requires energy to heat up the wire to its boiling temperature and to provide the latent heats of fusion and vaporization; (2) the wire atoms are given a considerable velocity (kinetic energy) due to the explosion; (3) a shock wave is produced in the surrounding atmosphere of the wire; (4) electromagnetic radiation is given off; e.g. optical, x-ray, infrared, ultraviolet, etc.; and (5) molecular bonds may be broken in the atmosphere around the wire. For a further discussion of exploding wire systems, see co-pending application U.S. Ser. No. 454,506, filed Dec. 29, 1982, and incorporated herein by reference.
As mentioned above, exploding wires of the type discussed have been used experimentally to enhance certain chemical and/or physical reactions. The fast inherent speed at which energy can be imparted to these reactions by an exploding wire system is attractive since such reactions, themselves, are extremely fast but are normally limited by how rapidly such energy can be added. However, as far as it is known, exploding wires of this type have not been used for enhancing such reactive processes on a commercial scale. This is believed to be due in part to the fact that (1) a practical method for fast, repeatable firing of an exploding wire have heretofore been lacking; and (2) the total energy levels have been much too low for these operations.